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JP2008011099

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DESCRIPTION JP2008011099
An object of the present invention is to make it possible to reproduce a more ideal sound field as
headphones corresponding to multi-channels. A drive unit for outputting a main audio
component of LFch, Cch, an auxiliary audio component of RFch, an auxiliary audio component of
LSch, an auxiliary audio component of RF, an auxiliary audio component of RF, and LFEch in the
left audio unit is individually provided for 5.1ch surround. Provided in In the right audio unit,
drive units for individually outputting the main audio component of RFch, the auxiliary audio
component of Cch and LFch, the main audio component of RSch, the auxiliary audio component
of LF, and LFEch are provided. Also, these drive units are arranged in the order of arrangement
corresponding to the channel sound source positions. The audio signal of the sub audio
component is generated by applying a filtering process and a delay process so that the signal
characteristic difference with respect to the main audio component is given. [Selected figure]
Figure 8
Headphone sound reproduction system, headphone device
[0001]
The present invention relates to a headphone sound reproduction system equipped with a
headphone device and adapted to perform sound reproduction, and to a headphone device
provided in such a headphone sound reproduction system.
[0002]
For example, it is known to perform sound reproduction with a channel configuration called a so-
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called multi-channel represented by 5.1 ch surround and the like.
Such a multi-channel audio source is generally output from each of the speakers arranged
according to the appropriate positional relationship corresponding to the number of channels,
and in this way, the playback output is performed. The audio signal of each channel is produced
on the premise that Then, when listening to the multi-channel sound that is actually reproduced
and output from the speaker, the sound images of various sound sources are localized around the
listening position, for example, more stereoscopic and more realistic than 2-channel stereo etc.
You can enjoy the sound effects with a sense.
[0003]
As described above, the original multi-channel sound reproduction should be performed by
arranging speakers for the number of channels, but even by headphone reproduction, it is as if
the speakers were actually arranged and listened to Signal processing techniques for enabling
sound images to be localized and audible at appropriate positions outside the listener's head have
been proposed, realized and are in widespread use.
[0004]
In such a signal processing technique, for example, the sound emitted from the sound source
corresponding to each channel is made to utilize the transfer function of the path until it reaches
the listener's left ear and right ear and can be heard.
The transfer function used in this case is considered to correspond to, for example, the transfer
characteristic of sound from the sound source to the eardrum of the listener, and is also referred
to as a head transfer function. Then, after assigning audio signals as sound sources for each
channel constituting the multi-channel to correspond to the left ear and the right ear, signal
characteristics based on the head-related transfer function are given to these audio signals. It will
be. That is, from the original sound of the sound signal of each channel, a signal having a
characteristic of reaching the left ear from the sound source position as the channel and a signal
of a characteristic reaching the right ear are generated. Then, the signal obtained by synthesizing
the signal having the head related transfer function of the path to reach the left ear of each
channel is reproduced and output as sound from the left drive unit of the headphone, and
similarly reaches the right ear of each channel A signal obtained by combining signals having
head-to-head transfer functions of up to paths is reproduced and output as sound from the right
drive unit of the headphone. In this way, for example, the listener can listen to the sound to be
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reproduced and output almost directly with the headphones with both ears, so that the sound
image is not localized in the head but, for example, a speaker corresponding to a multichannel is
actually arranged. Sound localization that is equivalent to listening in a noisy environment. That
is, it is possible to obtain an acoustic effect called so-called surround.
[0005]
Unexamined-Japanese-Patent No. 2003-274493
[0006]
However, since the above-described headphone sound reproduction system obtains a virtual
sound field by signal processing using the head transfer function to the last, the sound effect that
the user can actually hear is not sufficient. At present, it is not uncommon to feel that it is
sufficient.
One of the main causes is that the audio signal of each channel obtained based on the headrelated transfer function is synthesized as the audio signal of the left and right channels,
corresponding to each of the left and right drive units. In a multi-channel reproduction
environment in which speakers are actually arranged, sounds (sound waves) emitted from the
speakers of each channel are synthesized in space. The listener will hear this synthesized sound.
For example, in this case, even if signals having opposite phases are reproduced between
different channels, they will not be exactly canceled out by being synthesized in space, and this is
rather rich sound. It is a factor of getting a sense of place. On the other hand, in the abovedescribed headphone sound reproduction system, instead of synthesizing sounds in space,
synthesis is performed at the audio signal stage. Then, when the signals are in reverse phase
between different channels, the signals are exactly canceled each other, which makes the sense
of the sound field unnatural or inadequate. It leads to a thing. There is currently no effective
solution to the above problems, and the headphone sound reproduction system that can obtain
virtual sound fields corresponding to multiple channels is therefore more effective. It can be said
that there remains room for a faithful acoustic effect to be obtained.
[0007]
Therefore, in consideration of the problems described above, the present invention is configured
as a headphone sound reproduction system as follows. That is, a plurality of drive unit pairs
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corresponding to the left and right ears are provided corresponding to each of a plurality of
channels forming a predetermined channel configuration, and at least one of the drive unit pairs
is a virtual sound source of the corresponding channel. The main audio signal corresponding to
the main audio component that is supposed to reach the position corresponding to one ear from
the position is input to be reproduced and output, so that the reproduced and output sound can
be heard by one ear And an auxiliary audio signal corresponding to an auxiliary audio
component which is supposed to reach from the virtual sound source position of the
corresponding channel to the position corresponding to the other ear. And a secondary audio
compatible single-sided drive unit provided in such a manner that the audio reproduced and
output can be heard by the other ear. , It was decided to include the sub-audio signal
characteristic applying means for obtaining a sub-audio signal by providing a signal
characteristic corresponding to the difference between the predetermined characteristics of the
sub-audio components to the main audio component with respect to the main audio signal.
[0008]
In the above configuration, a set of drive units is provided corresponding to a predetermined
channel configuration. The drive unit has a structure including a diaphragm and the like, and
each of a set of drive units, which is a portion for outputting a sound by being driven by a drive
signal according to an audio signal, has a left ear and One of the drive units of the pair of drive
units is a main audio compatible one-side drive unit, and one of the drive units is one of the drive
units of the corresponding channel. The main audio signal corresponding to the main audio
component that is supposed to reach a position corresponding to one ear from the virtual sound
source position is input, reproduced and output, and the other drive unit is regarded as an
auxiliary audio compatible one-side drive unit. Input a sub-audio signal corresponding to the subaudio component that is supposed to reach the position corresponding to the other ear from the
virtual sound source position It is adapted to raw output. That is, as a basic concept of the
configuration according to the present invention, in reproducing the sound source position
corresponding to each channel, the sound signal of the sound component of which the sound
source of that channel reaches one ear (main sound signal) After generating audio signals (sub
audio signals) of audio components that reach the ear, these audio signals can be reproduced and
output so that they can be heard by the right or left ear by the independent drive units. It is said
that. With such a configuration, for example, the sounds that should reach the left and right ears
from the sound source position for each channel are respectively emitted from the drive unit and
are first synthesized in a space near the ears, I will reach the tympanic membrane.
[0009]
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As described above, according to the present invention, the sound that is supposed to come from
the sound source position for each channel to the left and right ears while being played by the
headphones is synthesized in space before being sent to the ears. It is made to arrive. This makes
it possible to provide a headphone sound reproduction system capable of reproducing a sound
field considered to be closer to an ideal than before.
[0010]
Hereinafter, the best mode for carrying out the present invention (hereinafter, referred to as an
embodiment) will be described. The present embodiment is intended to virtually realize sound
image localization obtained by a multi-channel configuration represented by, for example, 5.1 ch
surround as a headphone sound reproduction system. First, the basic configuration concept of
the technology for realizing such virtual sound image localization by headphone reproduction
will be described.
[0011]
Here, the simplest example is given for sound image localization of a sound source. That is, it is
assumed that the sound image localization of a single sound source in a certain positional
relationship with the listener is virtually reproduced by headphones. This is grasped as a
relationship between the listener M and one sound source Src which is said to be at a constant
angle and a constant distance with respect to the listener M, for example, as schematically shown
by the acoustic model in FIG. be able to. As shown in this figure, the sound emitted from the
sound source Src is given and transmitted as the transfer function Hl is folded to the left ear of
the listener M, and the transfer function Hr to the right ear. Is given and transmitted. Here, the
transfer functions Hl and Hr are head related transfer functions corresponding to the transfer
characteristics of sound from the sound source to the eardrum of the listener. Further, since the
sound source Src in this case is located on the left side in front of the listener M, among the
sounds reaching the left and right ears of the listener M from the sound source Src, the sound
reaching the left ear is The sound that reaches the right ear is a crosstalk component that the
sound that originally arrives at the left ear and that is heard is diffracted and heard by the right
ear, assuming that it is a direct sound main sound component, Therefore, the main voice
component can be treated as being a secondary voice component.
[0012]
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FIG. 18 shows the frequency characteristic A of the sound according to the path of the transfer
function H1 and the right ear of the listener M, which are said to be emitted from the sound
source Src and heard by the left ear of the listener M in FIG. It shows the frequency characteristic
B of the sound by the path of the transfer function Hr, which is supposed to be heard. As
described above, since the sound source Src in this case is located on the left front of the listener
M, the sound heard by the listener M's left ear is direct sound. On the other hand, the sound
heard by the left ear of the listener M is an indirect sound and a crosstalk component. The
difference between the frequency characteristic B and the frequency characteristic A is that the
sound pressure of the frequency characteristic B is smaller, which corresponds to this.
[0013]
In this way, the sounds emitted from one sound source Src to reach each of the left and right ears
to be heard have different frequency characteristics. Further, as shown in FIG. 17, there is a
distance difference Ds between the distance from the sound source Src to the left ear and the
distance from the right ear, and the sound source Src emits light according to the distance
difference Ds. The arrival time difference dl, which is the time difference for the left and right
ears to reach the left and right ears, also occurs. The transfer functions Hl and Hr shown in FIG.
17 give characteristic differences such as the frequency characteristic difference and the arrival
time difference to the original sound emitted from the sound source Src. And, as the sound image
localization ability of a person, from the difference of the predetermined characteristic such as
the frequency characteristic difference (here, the element of the volume difference is included
here) about the sound heard between the left ear and the right ear as described above , It is said
that the perception of the localization of the sound image is perceived. Based on this, in order to
reproduce the virtual sound image localization of one sound source by the headphone, the signal
characteristic difference corresponding to the main sound component and the sub sound
component as described above is given based on the sound signal of the original sound. Two
audio signals may be obtained, and one of the audio signals may be reproduced and output from
the drive unit corresponding to the left ear, and the other may be reproduced and output from
the drive unit corresponding to the right ear.
[0014]
Based on the above, as shown in the acoustic model of FIG. 19, the headphones reproduce the
sound image localization obtained by the left sound source Srcl and the right sound source Srcr
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disposed on the left and right front with respect to the listener M Consider the case. In this case,
first, the sound emitted from the left sound source Srcl reaches the left ear of the listener M
given the transfer function Hll as the main voice, and the transfer function Hlr given as the
subvoice reaches the right ear It is supposed to be. Also, the sound emitted from the right sound
source Srcr reaches the right ear of the listener M given the transfer function Hrr as the main
voice, and the transfer function Hrl given as the sub sound to the left ear of the listener M It shall
be reached.
[0015]
The configuration shown in FIG. 20 can be considered as the configuration of the signal
processing system for realizing the sound image localization by the left and right front shown in
FIG. 19 by headphone reproduction. First, in the configuration shown in FIG. 20, an original
audio signal Sl corresponding to the original sound emitted by the left sound source Srcl in FIG.
19 and an original sound emitted as the right sound source Scrr in FIG. The original audio signal
Sr is input. The original speech signal S1 is branched into a system directly input to the
synthesizer 13a and a system input from the filter 11b to the synthesizer 13b via the delay unit
12b. The original speech signal Sr is also branched into a system directly input to the synthesizer
13b and a system input from the filter 11a to the synthesizer 13a via the delay unit 12a.
[0016]
In the synthesizer 13a, as described above, the left (L) output channel is generated by
synthesizing the directly input original speech signal Sl and the signal obtained by processing the
original speech signal Sr by the filter 11a and the delay unit 12a. It is assumed that the drive unit
SPu-L corresponding to the left ear is used as a signal for voice output. In addition, the
synthesizer 13b synthesizes the directly input original speech signal Sr and the signal obtained
by processing the original speech signal Sl by the filter 11b and the delay unit 12b, as a signal
for the right (R) output channel, The drive unit SPu-R corresponding to the right ear is made to
output as sound. The actuality of these drive units is, for example, a portion provided with a
diaphragm of a predetermined material shape, and reproducing sound by driving the diaphragm
by a drive current obtained by amplifying an audio signal. . In other words, it is a speaker unit
adapted to reproduce sound near the ear such as headphones.
[0017]
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In the configuration shown in FIG. 20, first, the system from which the original voice signal Sl is
directly input to the synthesizer 13a and leading to the drive unit SPu-L corresponds to the main
voice component reaching from the left sound source Srcl to the left ear. This is equivalent to
providing a signal characteristic according to the transfer function Hll as described later. On the
other hand, the system from the original sound signal Sl to the drive unit SPu-R via the filter 11b,
the delay unit 12b, and the synthesizer 13b corresponds to the sub sound component reaching
from the left sound source Srcl to the right ear. And the filter 11b and the delay unit 12b give the
signal characteristic difference (frequency characteristic difference, arrival time difference dl)
with respect to the main voice component, so that the transfer function Hlr gives a signal
characteristic equivalent to that of being convoluted. . Similarly, the system in which the original
speech signal Sr is directly input to the synthesizer 13 b and reaches the drive unit SPu-R
corresponds to the main speech component reaching from the right sound source Srcr to the
right ear and corresponds to the transfer function Hrr. It is assumed that the signal characteristic
is given, and the system from the original sound signal Sr to the drive unit SPu-L via the filter
11a, the delay unit 12a, and the synthesizer 13a is a sub-audio component that reaches the left
ear from the right sound source Src. The filter 11a and the delay unit 12a provide a
characteristic difference with respect to the main sound component so as to give a signal
characteristic equivalent to the transfer function Hlr being convoluted.
[0018]
For example, as a general thing about headphones of 2-channel stereo by L and R, the
characteristics of the sound reproduced by the sound unit, including the frequency characteristic
of the reproduction sound of the drive unit, are actually listeners wearing headphones When
listening to the sounds reproduced from the acoustic units of the left and right ears, the balance
of the frequency band is set to sound natural. From this, at the stage when the sound is
reproduced by the headphone device, for example, the reproduced sound of each of the L and R
channels corresponds to the transfer function according to the path to reach each of the left and
right ears. Can be thought of as approximately given. Also as a headphone device corresponding
to the present embodiment, for example, a drive unit or the like is created on the premise of such
a thing. Based on the above, at least a main voice component in FIG. 20, a system in which signal
S1 is directly input to synthesizer 13a and reaches drive unit SPu-L, and signal Sr is directly to
synthesizer 13b. With respect to the system that is input and reaches the drive unit SPu-R, it is
considered equivalent to the transfer functions Hll and Hlr being convoluted by being output as a
sound from the drive unit without particularly performing filtering and delay processing. It will
be able to be understood as what can be obtained the characteristic sound. Then, as described
above, for the sub-audio components corresponding to the main audio component, the filter and
the delay unit give the frequency characteristic difference and the arrival time difference with
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respect to the main audio component according to the transfer function. It will be. As a result, the
main sound by the transfer function H11 to reach the left ear from the left sound source Srcl and
the sub sound by the transfer function Hlr to reach the right ear are reproduced and output from
the drive units SPu-L and SPu-R, respectively. In other words, if you listen to the component of
this sound, you can perceive that the left sound source Srcl is localized at an appropriate
position. Similarly, the main sound by the transfer function Hrr to reach the right ear from the
right sound source Srcr and the sub sound by the transfer function Hrl to reach the left ear are
respectively reproduced and output from the drive units SPu-R and SPu-L. As a result, when
listening to this sound component, it can be perceived that the right sound source Srcr is
localized at an appropriate position. That is, the listener can perceive a sound image localized by
the left sound source Srcl and the right sound source Srcr at an appropriate position on the left
and right front, and virtual sound image localization is realized.
[0019]
Here, the relationship between the headphone device corresponding to the system configuration
shown in FIG. 20 and the head of the listener is shown in FIG. The headphone device in this case
has a left sound unit 1L and a right sound unit 1R corresponding to each of the left and right
ears of the listener M as shown in FIG. Although not shown here, for example, the left acoustic
unit 1L and the right acoustic unit 1R are connected by a head band or the like so that a
structure attachable to the head is adopted. The drive units SPu-L and SPu-R are attached to the
left sound unit 1L and the left sound unit 1R, respectively, and the drive units SPu-L and SPu are
properly mounted on the head of the headphone device. -R are made to be in optimal positions
that can be heard by the left and right ears, respectively.
[0020]
Next, regarding the configuration of a headphone sound reproduction system corresponding to a
more practical multi-channel configuration based on the configuration corresponding to the two
sound sources (two-channel configuration) described with reference to FIGS. Explain with
reference to. Here, a case where the multi-channel configuration is made compatible with the 5.1
ch surround standard is taken as an example.
[0021]
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First, FIG. 22 schematically shows a model of a 5.1 ch surround channel configuration. As well
known, 5.1ch surround is also referred to as LF (Left Front) ch, C (Center) ch, RF (Right Front) ch,
LS (Left Surround) ch, RS (Right Surround) ch, and a subwoofer. A channel configuration of a
total of six channels of LFE (Low Frequency Effect) ch is adopted. For these channels, for
example, the ITU-R or the like defines an ideal sound source position, that is, the position and
height of the speaker with respect to the listening position (listener M). However, for LFEch, the
directivity is dull because the reproduction frequency band is considerably lower than other
channels, and it is difficult for listeners to feel a clear localization, so the definition of the sound
source position is loose. It is assumed.
[0022]
And in FIG. 22, as a sound source according to each of LFch, Cch, RFch, LSch, RSch, LFEch,
speaker SP-LF, SP-C, SP-RF, SP-LS, SP-RS, SP-LFE. Is shown, and a model is shown in which the
listener M listens to the sounds that are output from these speakers and reach the left ear and
the right ear, respectively. For example, as an arrangement position of these speakers according
to the standard of 5.1ch surround, the speaker SP-LF is arranged on the left front with respect to
the position of the listener M, the speaker SP-C is arranged on the center front, and the speakers
on the right front The SP-RF is disposed, the speaker SP-LS is disposed at the left rear, and the
speaker SP-RS is disposed at the right rear.
[0023]
Then, according to FIG. 19, the following transfer function (head transfer function) is obtained
for the path of sound reaching each of the right and left ears of the listener M from each speaker
under the channel configuration shown in FIG. Can be represented by Hlfl: Transfer function of
the path from the speaker SP-LF to the left ear as the main audio component Hlfr: Transfer
function of the path from the speaker SP-LF to the right ear as the auxiliary audio component
Hcl: Main audio / from the speaker SP-C Transfer function of the path to reach the left ear as an
auxiliary audio component Hcr: Transfer function of the path to reach the right ear as an
auxiliary audio / main audio component from the speaker SP-C Hrfl: to the left ear as an auxiliary
audio component from the speaker SP-RF Transfer function of the route to reach Hrfr: Transfer
function of the route from the speaker SP-RF to the right ear as the main audio component Hlsl:
Transfer function of the route from the speaker SP-LS to the left ear as the main audio
component Hlsr: speaker SP Transfer function of the path from the LS to the right ear as an
auxiliary audio component Hrsl: transfer function of the path from the speaker SP-RS to the left
ear as an auxiliary audio component H rsr: transfer function of the path from the speaker SP-RS
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to the right ear as the main audio component
[0024]
FIG. 23 shows an example of a headphone reproduction system compatible with 5.1ch surround,
configured based on the basic concept shown by FIGS. 19 and 20 described above. First, also in
this figure, a pair of drive units SPu-L and SPu-R corresponding to the left output channel and the
right output channel are provided as drive units. The left output channel audio signal obtained by
synthesizing the input audio signal by the synthesizer 13a is input to the drive unit SPu-L, and
the drive unit SPu-R is obtained by synthesizing the input audio signal by the synthesizer 13b.
The audio signal for the right output channel is input.
[0025]
Then, the audio signals of each channel as 5.1 ch surround are distributed as follows and input to
the synthesizers 13a and 13b. First, the LFch original speech signal is directly input to the
synthesizer 13a, and is input to the synthesizer 13b via the filter 11b and the delay value 12b.
Further, the RFch original speech signal is directly input to the synthesizer 13b, and is input to
the synthesizer 13a via the filter 11a and the delay unit 12b. The original audio signal of Cch is
branched into two systems after passing through the filter 11e and the delay device 12e, and
then the signals of the respective systems are respectively input to the synthesizer 13a and the
delay device 13b. The LSch original speech signal is input to the synthesizer 13a via the filter
11d and the delay unit 12d, and is input to the synthesizer 13b via the filter 11g and the delay
unit 12g. The RSch original speech signal is input to the synthesizer 13a via the filter 11c and
the delay unit 12c, and is input to the synthesizer 13b via the filter 11f and the delay unit 12f.
The original voice signal of z LFEch is first branched into two systems, and the signals of the
respective systems are directly input to the synthesizer 13a and the synthesizer 13b.
[0026]
In the configuration shown in FIG. 23, first, the configuration of the signal system corresponding
to the combination of LFch and RFch is the basics of the headphone system corresponding to the
two channels of left sound source Srcl and right sound source Srcr shown in FIG. It corresponds
to the configuration. For this purpose, the signal corresponding to the main voice component
(left output channel) of LFch is output from the synthesizer 13a by the drive unit SPu-L without
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passing through the filter and the delay unit, whereby the transfer function Hlfl It is an attempt
to obtain a sound with the same signal characteristics as the folded-in. Also, for the signal
corresponding to the LFch sub-audio component (right output channel), by passing the filter 11b
and the delay unit 12b, the frequency characteristic difference and arrival time difference of the
sub-audio with respect to the main audio are given. , The sound of the same signal characteristic
as the transfer function Hlfr is convoluted is obtained. Similarly, the transfer function Hrfl is
convoluted by causing the signal corresponding to the main voice component (right output
channel) of RFch to be output from the synthesizer 13b by the drive unit SPu-R without passing
through the filter and the delay unit. It is made to obtain a sound having the same signal
characteristics as that of the main voice, and the signal corresponding to the sub-voice
component (left output channel) of RFch is passed through the filter 11a and the delay unit 12a
to The frequency characteristic difference and the arrival time difference are given, and the
transfer function Hrfl is made to obtain a sound having the same signal characteristic as the
convoluted.
[0027]
In addition, the filter 11d provided corresponding to the main voice component (left output
channel) of LSch, and the delay unit 12d have the main characteristics of the LFch in order to
obtain the same signal characteristics as the corresponding transfer function Hlsl is convoluted.
Parameters (pass band characteristics, delay time) for giving characteristic differences (frequency
characteristic differences and arrival time differences) to speech components are set. That is,
based on the main voice component of LSch, the main voice components of LFch differ in the
route to reach the left ear depending on the sound source position of each other. The
characteristic difference is to be obtained by the filter 11 d and the delay unit 12 d. Furthermore,
the filter 11g provided corresponding to the LSch sub-audio component (right output channel)
and the delay unit 11g have the same LSch to obtain the same signal characteristics as the
corresponding transfer function Hlsr is convoluted. Set parameters to give characteristic
differences to the main speech component.
[0028]
In addition, the filter 11f and the delay unit 11f provided corresponding to the main speech
component (right output channel) of RSch have the main characteristics of the LFch in order to
obtain the same signal characteristics as the corresponding transfer function Hlsl is convoluted.
Parameters for giving a characteristic difference to the voice component are set. In addition, the
filter 11g provided corresponding to the LSch sub-audio component (right output channel) and
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the delay unit 11g have the same LSch in order to obtain the same signal characteristic as the
corresponding transfer function Hrsr is convoluted. Set parameters to give characteristic
differences to the main speech component.
[0029]
The Cch is branched to a signal system corresponding to the left output channel and the right
output channel after passing through the filter 11e and the delay unit 12e. Cch is a sound source
located in front of the listener M, as shown in FIG. For this reason, ideally, the transfer
characteristics Hcl and Hcr corresponding to the sounds of each system reaching the left and
right ears of the listener M are equivalent, and main voices such as LFch, RFch, LSch, RSch There
is no difference between the component and the sub-voice component. In other words, in Cch,
there is a substantial difference between the system corresponding to the listener M's left ear and
the system corresponding to the right ear, regardless of which is treated as the main audio
component and the sub audio component. There is no such thing. However, with reference to the
main sound components of LFch and RFch, there is a signal characteristic difference between the
sound components corresponding to the left and right ears of Cch. Therefore, if this signal
characteristic difference is given, the transfer characteristics Hcl and Hcr as Cch are obtained,
and the sound image localization is realized. The parameters of the filter 11e and the delay unit
12e are set so as to give this signal characteristic difference.
[0030]
Further, as described above with reference to FIG. 22, the LFEch has a low directivity in
comparison with the sound of other channels because the reproduction frequency band is low.
The same applies to headphone reproduction in this respect. Therefore, LFEch is branched
directly to the synthesizers 13a and 13b without giving any signal characteristic. Thus, in the
configuration shown in FIG. 23, for the audio signals of channels other than LFEch, the transfer
characteristic corresponding to the sound component reaching the left ear and the transfer
characteristic of the sound component reaching the right ear are convoluted. , And then output
from the drive unit SPu-L of the left output channel and the drive unit SPu-R of the right output
channel. Then, when the listener M listens to the sound output in this manner, sound image
localization corresponding to the sound source position shown in FIG. 22 is perceived.
[0031]
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By the way, according to the headphone reproduction system having the configuration shown in
FIG. 23, in principle, it becomes possible to listen to virtual sound image localization
corresponding to the channel configuration of 5.1 ch surround as described above. In reality, it
has been found that sound image localization may not be perceived well, such as becoming
sparse or unnatural. One of the main causes of the cause is that the audio components for each
channel to reach each of the left and right ears are electrically synthesized at the stage of the
audio signal using the synthesizers 13a and 13b. Be
[0032]
In the original sound reproduction system as 5.1ch surround, for example, the speakers of each
channel are arranged according to FIG. 22, and the corresponding channel sound is reproduced
and output from these speakers. In this case, sound components emitted from the speakers of
each channel to reach the left and right ears of the listener M are synthesized in space and
transmitted to the tympanic membrane. For example, voices reproduced between channels may
be in the opposite phase and in phase with each other. In principle, opposite-phase sounds cancel
each other and can not be heard, and in-phase sounds reinforce each other, but when
synthesized in space, they are canceled or reinforced properly due to the influence of the
surrounding environment, etc. It is thought that it is difficult to do something like this, and such a
phenomenon is linked to the fact that a rich sound field feeling can be obtained. However, when
the sounds in such a phase relationship are electrically synthesized at the stage of the speech
signal, they will almost exactly cancel or reinforce each other, which may cause, for example,
unnatural hearing. It becomes a factor that causes the user to perceive that the feeling of sound
field is not good, for example.
[0033]
In addition, individual differences among actual listeners may be greatly influenced as another
main cause of the deterioration in the sound image localization feeling. The transfer functions
used in the headphone reproduction system described so far with reference to FIGS. 17 to 23 are
called head transfer functions, and represent, for example, transfer characteristics of the sound
path from the sound source to the eardrum of the listener. It is supposed to be. For this reason, in
the head-related transfer function, a characteristic component that is reflected by the human
auricle to reach the tympanic membrane is also included. In reality, there are individual
differences in the shape of human auricle, and it is difficult to set a head related transfer function
corresponding to such a difference. Therefore, in setting the head related transfer function, the
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auricle shape set as a standard is assumed by an appropriate method. However, in the headrelated transfer function, the proportion of the characteristic imparted by the pinna shape is
correspondingly high. In addition, the shape of a person's pinnacle in reality may be considered
to be different for each individual, and the individual difference is also correspondingly large. For
this reason, for example, for a listener having a pinnacle having a shape considerably different
from the pinna shape set as a standard, a listener will hear a sound far from the sound by the set
transfer function, and as a result, it is not good Sound image localization is to be perceived.
[0034]
Therefore, in the present embodiment, a headphone reproduction system configured to obtain a
good virtual sound image localization feeling is provided by excluding the above-described
factors as much as possible. Hereinafter, the configuration for this will be described.
[0035]
First, FIG. 1 shows a basic acoustic model as a premise in the headphone reproduction system
according to the present embodiment. This figure shows a case where the left sound source Srcl
and the right sound source Srcr are set at symmetrical positions in front of the listener M
(listening position), as in the case of FIG. For example, in the acoustic model shown in FIG. 19, the
transfer functions Hll, Hlr, Hrr, and Hrl of sounds reaching left and right ears from the left sound
source Srcl and the right sound source Srcr correspond to the sound path from the sound source
position to the eardrum. The head transfer function is determined, and therefore, the
measurement point is considered to be in the pinnae corresponding to the tympanic membrane.
On the other hand, in the present embodiment, the measurement points of the sound reaching
left and right ears from the left sound source Srcl and the right sound source Srcr are shown as
space measurement ranges P1 and P2, respectively, in the outer vicinity of the left and right
pinna It is assumed that the spatial position range to be In the space measurement ranges P1 and
P2, as shown in FIG. 2, measurement positions corresponding to the respective sound sources are
set. First, in the space measurement range P1, a measurement point Pll of a sound at which the
left sound source Srcl reaches the left ear and a measurement point Prl of a sound at which the
right sound source Srcr reaches the left ear are set. Further, in the space measurement range P2,
a measurement point Prr of sound where the right sound source Srcr reaches the right ear and a
measurement point Plr of sound where the left sound source Srcl reaches the left ear are set.
Note that setting of the positions of these measurement points in the horizontal direction
(horizontal alignment direction) and the vertical direction (height direction), and the distance
from the pinna etc. will be described later with reference to FIG. It is determined in accordance
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with the arrangement position of the drive unit for reproducing and outputting each of the four
sounds in the case of being configured. That is, these measurement points (Pll, Prl, Prr, Plr) are to
be positions in space where the drive unit of the corresponding sound is arranged. By setting the
measurement points in this manner, the transfer function of the sound reaching each of the left
and right ears from the left sound source Srcl and the right sound source Srcr in the present
embodiment can be obtained up to immediately before reaching the pinna. It is supposed to
correspond to the spatial path, and the influence of the pinna will be obtained as excluded. In FIG.
19, main sound components and sub sound components reaching left and right ears from left
sound source Srcl and main sound components and sub sound components reaching right and
left ears from right sound source Srcr are shown in FIG. Hll, Hlr, Hrr, and Hrl, respectively, but
transfer functions for which the influence of the pinnacle treated in this embodiment is excluded
as shown in FIG. 1 are sHll, sHlr, sHrr, and sHrl. To
[0036]
Next, FIG. 3 shows a basic configuration corresponding to the acoustic model of FIG. 1 as a
configuration example of the audio signal processing system of the headphone sound
reproduction system of the present embodiment. In the configuration of FIG. 3, an original
speech signal Sl corresponding to the original sound emitted by the left sound source Srcl of FIG.
1 and an original speech signal corresponding to the original sound emitted as the right sound
source Srcr of FIG. It is made to input Sr. In addition, the original speech signal Sl is branched
into two systems corresponding to the main speech component reaching the left ear from the left
sound source Srcl and the sub sound component reaching the right ear, and the system
corresponding to the main speech component is By performing reproduction and output by the
drive unit SPu-L without applying filtering and delay processing in particular, it is possible to
obtain a voice equivalent to the transfer function sH11 being convoluted. Here, for the system
corresponding to the main voice component, it is supposed that the signal characteristic
equivalent to that of the transfer function sHll being convoluted is given by not performing the
filtering process and the delay process in particular. The voice signal of the system
corresponding to the main voice component in the above is for the same reason as not
performing the filtering process and the delay process. The same applies to a system which
causes the drive unit SPu-R to output the original audio signal Sr corresponding to the main
audio component of the right sound source Scrr, which will be described later. Also, the system
corresponding to the sub-audio component from the left sound source Srcl is made to be
reproduced and output by the drive unit SPu-f (L) after passing through the filter 11-f (L) and the
delay device 12-f (L). To do. In this embodiment, although the transfer function from which the
influence of the auricle is removed is given, the signal characteristics of the sound measured
from the one sound source to the left ear and measured at the appropriate measurement point,
and the right ear Between the signal characteristics of the sound reached at the point of
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16
measurement and measured at the measurement point, the difference in the frequency
characteristics and the arrival time still occur due to the difference in the arrival angle and the
arrival direction of the sound. Is also represented as. Therefore, depending on the filter 11-f (L)
and the delay unit 12-f (L), the transfer function sHrl is convoluted as a result of giving a signal
characteristic difference with respect to the main sound component from the left sound source
Srcl. To obtain signal characteristics equivalent to
[0037]
In addition, the original audio signal Sr is also branched into two systems corresponding to the
main audio component reaching the right ear from the right sound source Srcr and the auxiliary
audio component reaching the left ear, and the system corresponding to the main audio
component is The signal is reproduced and output by the drive unit SPu-R without particularly
applying filtering and delay processing, and a sound equivalent to the transfer function sHrr
being convoluted is obtained. Also, the system corresponding to the sub sound component from
the right sound source Srcr passes the filter 11-f (R) and the delay unit 12-f (R), and the signal
characteristic difference for the main sound component from the right sound source Srcr is And
output by the drive unit SPu-f (R). As a result, the sound with the signal characteristics equivalent
to the transfer function sHlrl being convoluted is reproduced.
[0038]
For example, in the configuration of the headphone reproduction system according to FIG. 20
described above, only one drive unit is provided for each of the left and right output channels,
and the two sound sources correspond to the sound that reaches the left ear and is heard. Sound
signal and the sound signal corresponding to the sound that reaches the right ear to be heard are
synthesized and then output by the drive units SPu-L and SPu-R of the left and right output
channels. . On the other hand, in the present embodiment, the audio signals corresponding to the
sound that is supposed to reach the left ear side and the right ear side from the respective sound
sources of the left sound source Srcl and the right sound source Srcr are left and right output
channels (L, R) Instead of combining them individually, they are output from independent drive
units. That is, in the present embodiment, an output channel, that is, the drive unit SPu −
corresponds to each sound signal corresponding to the sound that is supposed to reach the left
ear side and the right ear side from each sound source of the left sound source Srcl and the right
sound source Srcr. L is provided. Here, output channels L, R, f (R), f (L) are shown corresponding
to each of drive units SPu-L, SPu-R, SPu-f (R), and SPu-f (L). ing.
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17
[0039]
FIG. 4 schematically shows an example of the arrangement structure of drive units in the left and
right acoustic units as an example of the headphone device corresponding to the configuration of
the audio signal system shown in FIG. As shown in this figure, first, in the left acoustic unit 1L of
the headphone device, drive units SPu-L, SPu-f (R) are provided, and the sound reproduced by
these drive units by the left ear To be heard. Further, in the right acoustic unit 1R, drive units
SPu-R and SPu-f (L) are provided so that sounds reproduced by these drive units can be heard by
the right ear. In addition, as the arrangement of the drive unit in the left acoustic unit 1L, first,
the drive unit SPu-L is arranged to correspond to the position corresponding to the measurement
point Pll in FIG. This position is regarded as, for example, a reference position in which there is
no bias either forward or backward with respect to the ear. The drive unit SPu-f (R) is arranged in
front of the drive unit SPu-L, for example, at a position corresponding to the measurement point
Prl separated by a predetermined distance difference DS1. Similarly to the arrangement of the
left acoustic unit 1L, the arrangement of the drive unit in the right acoustic unit 1R is also such
that the drive unit SPu-R is arranged corresponding to the reference position considered to
correspond to the measurement point Prr in FIG. The drive unit SPu-f (L) is disposed at a position
corresponding to the measurement point Plr which is separated forward by the distance
difference DS1 with respect to the drive unit SPu-R.
[0040]
In the basic configuration of the headphone reproduction system as the present embodiment
shown in FIGS. 3 and 4, first, for the left sound source Srcl, the left ear listens to the main sound
component outputted from the drive unit SPu-L, The right ear is made to listen to the sub-audio
component output from the drive unit SPu-f (L). At this time, since the drive unit SPu-f (L) is
located in front of the drive unit SPu-R, which is disposed with respect to the right ear, the sound
of this sub-audio component is made to come from the front. Will reach the ear. As a result, the
listener can perceive the sound of the left sound source Srcl as being localized to the left front.
Similarly, for the right sound source Srcr, the right ear listens to the main audio component
output from the drive unit SPu-R, and the left ear detects the sub audio component output from
the drive unit SPu-f (R). It is made to listen. Since the drive unit SPu-f (R) is also located forward
of the drive unit SPu-L, which is disposed on the left ear side in a standard manner, the sound of
this sub audio component also arrives from the front and reaches the ear As a result, the sound
of the right sound source Srcr can also be perceived as being localized to the left front. That is, it
is possible to perceive the sound image localization of the left sound source Srcl and the right
sound source Srcr.
10-05-2019
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[0041]
Then, in the left ear of the listener M, the main sound component from the left sound source Srcl
corresponding to the output channel L and the sub sound component from the right sound
source Srcr corresponding to the output channel f (R) It will be synthesized and heard in the
space in 1L. Similarly, in the right ear of the listener M, the main sound component from the
right sound source Srcr corresponding to the output channel R and the sub sound component
from the left sound source Srcl corresponding to the output channel f (L) are After being
synthesized in the space in the sound unit 1R, the sound arrives and can be heard. In this
manner, in the headphone device of the present embodiment, the sound of the output channel
which is supposed to reach each ear from the sound source is reproduced by the independent
drive unit, and then synthesized in the space close to the left and right ears. ing. For this purpose,
for example, as in the case where a sound signal corresponding to a sound that is supposed to
reach each ear from a sound source is electrically synthesized and then output as a sound,
signals of opposite phase and in phase cancel each other out properly. It also eliminates the
phenomena of strengthening and strengthening each other. This makes it possible to obtain a
better sound field feeling.
[0042]
Also, as in the present embodiment, the fact that the sound for each output channel, which is
supposed to reach each ear from the sound source, is synthesized in space before reaching the
ear means that the drive unit It can be said that the emitted sound is synthesized in space,
reflected by the pinna and then reaches the tympanic membrane. Therefore, as in the present
embodiment, a transfer characteristic (frequency characteristic, delay time difference) excluding
the influence of the pinna is given to the sound signal for each output channel which is supposed
to reach each ear from the sound source. For example, the characteristic that changes
corresponding to this pinna can be formed by the pinna of the actual listener individual. This
means that it becomes possible to feel a good sound image localization regardless of individual
differences such as the shape of the pinna, for example. In this way, the headphone reproduction
system of the present embodiment is such that a sense of sound localization that is better than
ever can be obtained for more people.
[0043]
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19
By the way, the delay time of the delay unit 12-f (R) and the delay unit 12-f (L) shown in FIG. 3 is
the main voice from one sound source position to one ear as described above. An arrival time
difference determined in accordance with the distance until the component reaches and the
distance until the sub audio component reaches the other ear is given to the audio signal of the
sub audio component. For example, in the case of the configuration shown in FIG. 20, the main
voice component of one sound source and the sound of the sub-voice component of the other
sound source are synthesized at the stage of the voice signal. It is best to give the time difference
as it is. However, in the present embodiment, as shown in FIG. 4, for example, in the case of the
left acoustic unit 1L, the physical distance DS1 is given to the arrangement position of the drive
unit SPu-L and the drive unit SPu-f (R). Therefore, the output from the drive unit SPu-f (R) takes
time for the main sound of the left sound source Srcl output from the drive unit SPu-L to reach
the left ear according to the distance DS1. There will be a delay in time for the sub sound of the
right sound source Srcr to reach the left ear. Therefore, in order to obtain the arrival time
difference of the best mode, according to the distance from the left sound source Srcl to the main
audio component reaching the left ear and the distance from the sub sound component to the
right ear. From the determined arrival time difference, the delay time corresponding to the
distance DS1 should be set to the delay unit 12-f (R).
[0044]
Subsequently, a configuration example of a headphone sound reproduction system compatible
with multiple channels based on the basic configuration described with reference to FIGS. 1 to 4
will be described. Also here, as a multi-channel configuration, the example is given to the 5.1 ch
surround standard.
[0045]
First, FIG. 5 shows a 5.1 ch surround sound model corresponding to the present embodiment.
Also as the acoustic model shown in this figure, for example, as in the case shown in FIG. 22, as
the sound source corresponding to each of LFch, Cch, RFch, LSch, RSch, LFEch, the speakers SPLF, SP-C, SP- RF, SP-LS, SP-RS, and SP-LFE are shown. Also, the arrangement of these speakers is
the same as in FIG. However, in the present embodiment, transmission of each sound that
reaches the left and right ears of the listener M from the sound source (speaker) of each channel
in configuring the headphone sound reproduction system corresponding to 5.1 ch surround As
for the function, as described with reference to FIG. 1, the one in which the influence of the pinna
is excluded is used. That is, in the vicinity of the outer sides of the left and right auricles, the
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measurement is performed at the measurement points set in the space measurement ranges P1
and P2, which are a collection of measurement points in space where the drive unit
corresponding to each sound is located. , The transfer function of the sound from each sound
source is used. An example of setting measurement points in the space measurement ranges P1
and P2 in this case is shown in FIG. First, in the space measurement range P1 corresponding to
the left ear, the measurement point Pcl of the sound arriving from the SP-C is set in front of the
measurement point Plfl corresponding to the sound arriving from the speaker SP-LF, In the
further forward of this, a measurement point Prfl of the sound arriving from the speaker SP-RF is
set. In addition, the measurement point Plsl of the sound arriving from the speaker SP-LS is set
behind the measurement point Plfl of the reference, and the measurement point Prsl of the sound
arriving from the speaker SP-RS is set further backward doing. In the space measurement range
P2 corresponding to the right ear, the measurement point Pcr of the sound arriving from the SPC is set in front of the measurement point Prfr corresponding to the sound arriving from the
speaker SP-RF, The measurement point Plfr of the sound arriving from the speaker SP-LF is set
further forward of this. Further, the measurement point Prsr of the sound arriving from the
speaker SP-RS is set behind the measurement point Prfr of the reference, and the measurement
point Plsr of the sound arriving from the speaker SP-RS is set backward further doing. And, as
shown in FIG. 5, the transfer function corresponding to each sound is expressed as follows. sHlfl:
transfer function of the path from the speaker SP-LF to the left ear side (measurement point Plfl)
as the main audio component sHlfr: from the speaker SP-LF to the right ear side (measurement
point Plfr) as the auxiliary audio component Transfer function sHcl: Transfer function of the path
from the speaker SP-C to the left ear side (measurement point Pcl) as the main voice / sub-voice
component sHcr: from the speaker SP-C as the sub voice / main voice component right ear side
(measurement Transfer function of the path reaching the point Pcr) sHrfl: Transfer function of
the path reaching from the speaker SP-RF to the left ear side (measurement point Prfl) as an
auxiliary sound component sHrfr: from the speaker SP-RF as a main sound component to the
right ear side Transfer function of the path to reach (measurement point Prfr) sHlsl: Transfer
function of the path to reach the left ear side (measurement point Plsl) from the speaker SP-LS as
main audio component sHlsr: right from the speaker SP-LS as sub-audio component Ear side
Transfer function of the path reaching the measurement point Plsr) sHrsl: Transfer function of
the path arriving from the speaker SP-RS to the left ear side (measurement point Prsl) as an
auxiliary sound component sHrsr: right ear as a main sound component from the speaker SP-RS
Transfer function of the path to reach the side (measurement point Prsr)
[0046]
Subsequently, a configuration example of a signal system compatible with 5.1 ch surround will
be described as the headphone sound reproduction system according to the present embodiment
with reference to FIG. In the description here, among the filter 11 and the delay unit 12 shown in
10-05-2019
21
FIG. 7, the one shown by a broken line is omitted and the configuration in which the signal
processing system is simplified is described as a premise.
[0047]
First, in this configuration, 12 outputs corresponding to sound components reaching the left ear
and the right ear for each of six channels (LFch, Cch, RFch, LSch, RSch, LFEch) constituting 5.1ch
surround Channels (LF, f (LF), RF, f (RF), C (L), C (R) LS, f (LS), RS, f (RS), LFE (L), LFE (R)) It is
supposed to be provided. In addition, as drive units, drive units SPu-LF, SPu-f (LF), SPu-RF, SPu-f
(RF), SPu-C (L), SPu-C (L) corresponding to each of these output channels. R), SPu-LS, SPu-f (LS),
SPu-RS, SPu-f (RS), SPu-LFE (L) and SPu-LFE (R) are provided. Then, a signal system for each
audio signal of each channel as 5.1 ch surround is formed as follows. In addition, since the
description here presupposes the above-mentioned simple structure, the filter 11 and the delay
device 12 which are shown with a broken line are handled as what is abbreviate | omitted.
[0048]
First, in the configuration of the signal system shown in FIG. 7, the basic components
corresponding to FIG. 3 are provided as signal systems corresponding to LFch and RFch. That is,
the left sound source Srcl and the right sound source Srcr in FIG. 3 correspond to the LFch and
RFch in FIG. 7 on the input source side, and the output channel side in FIG. Three L, f (L), R, and f
(R) correspond to LF, f (LF), RF, and f (RF), respectively.
[0049]
According to the above-described correspondence, first, the LFch original audio signal is
branched into two systems, and one of the systems is directly subjected to the drive unit SPu- as
the main audio component without being subjected to the filtering process and the delay process.
It is made to be input to LF. The transfer function sHlfl is given by this system. The other system
passes through the filter 11-f (LF) and the delay device 12-f (LF) to be given the signal
characteristic of the difference with respect to the main audio component, and the drive unit SPuf (LF , And the transfer function sHlfr is made to be convoluted so that the given voice is
reproduced. In addition, the original voice signal of RFch, which is the sound source to the left
and right of LFch, is also branched into two systems of the main voice component and the sub
voice component, and the system of the main voice component is subjected to filter processing
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and delay processing. The transfer function sHrfr is given without being directly input to the
drive unit SPu-RF. Further, the system of the sub audio component passes through the filter 11-f
(RF) and the delay unit 12-f (RF) to be given the signal characteristic of the difference with
respect to the main audio component, and the drive unit SPu-f. (LF) is input so that the sound to
which the transfer function sHrfl is given is reproduced. Then, the remaining LSch, RSch, Cch,
and LFEch signal systems are provided for this basic component as follows.
[0050]
The Lsch original audio signal is directly input to the drive unit SPu-LS without filtering or the
like for the main audio component, whereby the audio to which the transfer function sHlsl is
given is reproduced. . As for the sub audio component, the transfer function sHlsr is given by
inputting it to the drive unit SPu-f (LS) via the filter 11-f (LS) to give a signal characteristic
difference with respect to the main audio component. Get playback audio. In addition, the Rsch
original audio signal, which is symmetrical with respect to LSch, is directly input to the drive unit
SPu-RS without filtering for the main audio component, whereby the transfer function sHrsr is
given. Audio to be played back. As for the sub audio component, the transfer function sHrsl is
given by inputting to the drive unit SPu-f (RS) via the filter 11-f (RS) to give a signal characteristic
difference to the main audio component. Get playback audio.
[0051]
In addition, as the original audio signal of Cch is also branched into two, one system is directly
input to the drive unit SPu-C (L), and the other system is directly input to the drive unit SPu-C (R)
I am trying to As described above with reference to FIG. 23, Cch is a sound source localized in
front of the front of the listener M, and therefore, at the positions (measurement points P1 and
P2) corresponding to the left and right ears of the listener M With respect to the observed sound,
no signal characteristic difference corresponding to the main sound component and the sub
sound component is generated, and the transfer functions sHcl and sHcr of each sound are
considered to be equivalent. For this reason, as described above, the original sound signals of the
same Cch are input to the drive units SPu-C (R) and SPu-C (L) corresponding to the left and right
acoustic units.
[0052]
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23
Further, as to the voice of LFEch, the directivity is dull as described with reference to FIG.
Therefore, assuming that it is sufficient if the same sound is output from the left and right
acoustic units, here, the original voice signal of LFEch is branched into two systems, and the
signals of each system are The drive units SPu-LFE (L) and SPu-LFE (R) corresponding to the
above audio units are to be directly input.
[0053]
Here, as the sound reproduction characteristics of the twelve drive units shown in FIG. 7, the
same one is used. Assuming that the acoustic unit reproduction characteristics are equal, it
becomes easy to set the passband characteristics of the filter 11. However, drive units SPu-LFE
(L) and SPu-LFE (R) corresponding to LFEch are required to reproduce a considerably lower band
as compared to the frequency band to be reproduced by other drive units. The sound
reproduction characteristics may be adapted to such low frequency reproduction.
[0054]
Subsequently, an arrangement example of the drive unit in the headphone device corresponding
to the configuration of the signal system shown in FIG. 7 will be described with reference to FIGS.
First, as shown in FIG. 8 and FIG. 9, in the left acoustic unit 1L of the headphone device, the drive
unit SPu-f (the center position of the sound producing portion is along the horizontal imaginary
line H from the front to the back). RF), SPu-C (L), SPu-LF, SPu-LS, and SPu-f (RS) are arranged.
Further, in this case, the drive unit SPu-LFE (L) is arranged below the position where the drive
units SPu-C (L) and SPu-LF are arranged. Further, in the right acoustic unit 1R of the headphone
device, the drive units SPu-f (LF), SPu-C (R), SPu are arranged so that the center position of the
sound producing unit is along the horizontal virtual line H from the front to the rear. -RF, SPu-RS,
SPu-f (LF) are arranged. The drive unit SPu-LFE (R) is arranged below the position where the
drive units SPu-C (R) and SPu-RF are arranged.
[0055]
In the aspect of the arrangement described above, first, drive units corresponding to channels
other than LFEch are arranged along the same horizontal imaginary line H in the left and right
acoustic units. In this arrangement mode, it corresponds to the position of each channel sound
source as 5.1 ch surround. That is, for example, on the side of the left acoustic unit 1L, the drive
10-05-2019
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unit SPu-LS corresponding to the main audio component of LSch is disposed behind the drive
unit SPu-LF corresponding to the main audio component of LFch. Further, in front of the drive
unit SPu-LF, a drive unit SPu-C (L) corresponding to Cch is disposed. Thus, it is understood that
the drive units corresponding to the sound of the channel corresponding to the main sound
component and the tonic component are arranged corresponding to the position of the channel
sound source. Further, among the drive units corresponding to the sub audio component, the
drive unit SPu-f (RF) corresponding to the sound source ahead is arranged on the front side with
respect to the drive unit SPu-LF at the reference position, The drive unit SPu-f (RS) corresponding
to the sound source is disposed behind the reference position. Further, on the side of the right
acoustic unit 1R, the drive units SPu-f (RF), SPu-C (R), SPu-LF, SPu-LS, and SPu- are arranged in a
symmetrical positional relationship with the left acoustic unit 1L. The f (RF) is arranged, so that
the drive unit corresponding to the main sound component is also arranged corresponding to the
position of the channel sound source on the side of the right sound unit 1R, and as a sub sound
component The drive unit SPu-f (LF) corresponding to the sound source in front is disposed on
the front side with respect to the reference position, and the drive unit SPu-f (LS) corresponding
to the sound source in the rear is disposed behind the reference position. It has become.
[0056]
In this case, as described above, among the drive units arranged in the left and right acoustic
units, the arrangement positions of the drive units SPu-LF and SPu-RF are used as a reference.
That is, as for the drive units SPu-LF and SPu-RF, positions at which the output sound reaches the
left and right ears are set to positions that are not biased forward or backward. This position is
equivalent to the arrangement of the left and right drive units, for example, when a headphone
device as a normal L, R stereo is to be configured. In addition, the positional relationship in the
front-rear direction with respect to the other drive units is set.
[0057]
In addition, the drive units SPu-f (RF) and SPu-f (LF) are located forward of the reference position
in each of the left and right acoustic units, so that sound images as LFch and RFch are localized
at an appropriate position ahead. What will be heard is as described above with reference to FIG.
Also, depending on the fact that the drive units SPu-f (LF) and SPu-f (RF) are behind the reference
position in each of the left and right acoustic units, according to the explanation of FIG. The
sound image is localized and can be heard. Then, the sounds of Cch and LFEch are spatially
synthesized in the acoustic unit together with the sounds of LF, RF, LSch, and RSch described
above, and then reach the left and right ears. As a result, the listener can clearly feel the sound
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image localization according to the sound source position according to the channel configuration
shown in FIG. 5, for example.
[0058]
Furthermore, according to FIG. 8, in each acoustic unit, five drive units ([SPu-f (RF), SPu-C (L),
SPu-LF) corresponding to other than LFEch arranged along virtual line H are provided. , SPu-LS,
SPu-f (RF)] [drive units SPu-f (RF), SPu-C (L), SPu-LF, SPu-LS, SPu-f (RF)] respectively in the frontrear direction The angle is given along the curved surface surrounding the ear rather than being
disposed in a plane. Thereby, for example, the arrangement positional relationship of the drive
unit is made closer to the sound source position in the channel configuration of 5.1 ch surround,
and the sound image localization feeling is made clearer. As described above, the mounting angle
and the like when the drive units are arranged in a curved manner may be set by verifying the
feeling of sound image localization and the like that are actually obtained.
[0059]
By arranging the drive unit along the longitudinal direction of the listener as shown in FIG. 9, the
following operation can be obtained. For example, focusing on the positional relationship
between the drive unit SPu-f (RF) corresponding to the sub-voice component of RFch and the
drive unit SPu-LF corresponding to the main voice component of LFch in the left acoustic unit 1L,
For the drive unit SPu-LF, the drive unit SPu-f (RF) is located farther from the drive unit SPu-LF.
This means that, for example, the distance DS1 described above with reference to FIG. 4 exists
between the drive unit SPu-LF and the drive unit SPu-f (RF). Therefore, a time difference occurs
in which the time for sound to reach the left ear from the drive unit SPu-f (RF) is longer than the
time for sound to reach the left ear from the drive unit SPu-LF. The arrival time of the sound to
the ear for the drive unit SPu-LF and that of the drive unit SPu-RF symmetrical to this is
equivalent. As the signal characteristics of the sub-audio component, it is necessary to give an
arrival time difference with respect to the main audio component, but in view of the above, this
arrival time difference is determined by the positions of drive unit SPu-f (RF) and drive unit SPuL. The relationship means that you can earn money. Thereby, as will be described later, in the
present embodiment, the delay unit in the system for outputting the sound by the drive unit SPuf (RF) can be omitted, and a simple signal processing system configuration can be realized. It is.
For the same reason as this, the drive units SPu-f (LF) in the right acoustic unit 1R are also
arranged in the same positional relationship as the drive units SPu-f (RF). Further, the drive unit
SPu-f (RS) in the left acoustic unit 1L is also disposed behind the drive unit SPu-LS, and similarly,
the drive unit SPu-f (LS) in the right acoustic unit 1R is also more than that of the drive unit SPu-
10-05-2019
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RS. Also placed behind.
[0060]
The measurement points in the space measurement ranges P1 and P2 previously shown in FIG. 6
are set corresponding to the spatial arrangement position of the drive unit shown in FIGS. That is,
the measurement points Prfl, Pcl, Plfl, Plsl, Prsl in the space measurement range P1
corresponding to the left ear are respectively drive units SPu-f (RF), SPu-C (L), SPu-in the left
acoustic unit 1L. It should be set in consideration of the correspondence with the arrangement
positions of LF, SPu-LS, and SPu-f (RS). Similarly, measurement points Plfr, Pcr, Prfr, Prsr, Plsr in
the space measurement range P2 corresponding to the right ear are respectively drive units SPuf (LF), SPu-C (R), and the like in the right acoustic unit 1R. It should be set in consideration of the
correspondence with the arrangement positions of SPu-RF, SPu-RS, and SPu-f (LS).
[0061]
Further, FIG. 10 shows a modification of the arrangement of the drive units in the acoustic unit.
In this figure, the same parts as in FIG. 9 are assigned the same reference numerals and
explanation thereof is omitted. In FIG. 10, first, among the five drive units corresponding to
channels other than LFEch provided in left acoustic unit 1L, drive units SPu-f (RF), SPu-C (L), and
SPu-LF are shown. The virtual horizontal line Hu, which is disposed along the virtual horizontal
line H similar to that of No. 9, whereas the drive units SPu-LS and SPu-f (RS) are set at a position
higher than the virtual horizontal line H by a predetermined amount. It is arranged along the top.
Similarly, in the right acoustic unit 1R, drive units SPu-f (LF), SPu-C (R), and SPu-RF are disposed
along the virtual horizontal line H, and drive units SPu-RS, SPu-f ( The LS) is arranged along the
virtual horizontal line Hu. In other words, in the 5.1ch surround channel configuration, the drive
unit corresponding to the main audio component and the secondary audio component whose
source is LSch and RSch, which are located relative to the listening position, is positioned higher
than the drive units of other channels. It is set to be For example, in the case of performing sound
reproduction by a speaker system corresponding to a multi-channel configuration such as an
actual 5.1 ch surround, a speaker of a channel arranged at a position behind the listening
position It is empirically known that when placed at a position slightly higher than the speaker of
the channel placed at the position where the sound is localized, a good sound image localization
feeling can be obtained. The arrangement example of the drive unit shown in FIG. 10 is an
application of this, and as a result, it is possible to obtain a better sound field as the headphone
device of the present embodiment. When the arrangement position of the drive unit is changed in
the height direction as shown in FIG. 10, the position in the height direction of each
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measurement point in space measurement ranges P1 and P2 should be changed and set. It will
be.
[0062]
By the way, as described above, the description about FIG. 7 above is premised on a simplified
configuration in which the filter 11, the delay unit 12 and the like indicated by broken lines are
omitted. However, in the signal system shown in FIG. 7, the filter 11 for providing the frequency
characteristic difference with the main voice is provided without omission for the system of the
secondary voice in LFch, RFch, LSch, and RSch. Although this filter 11 can be configured by, for
example, a digital filter, an analog filter is used as the filter 11 in consideration of simplification
and cost reduction of the signal processing system as much as possible. It is also conceivable.
[0063]
FIG. 11 shows a configuration example of the filter 11 by an analog circuit. In this figure, first,
the inductor L1 is inserted in series in the first stage to which a signal is input, and the filter
sections 11a, 11b and 11c are sequentially connected to the subsequent stage of the inductor L1.
It is assumed. The filter unit 11a is formed by connecting a series circuit including an inductor
L2, a resistor R2, and a capacitor C2 and a parallel circuit including an inductor L3, a resistor R3,
and a capacitor C3 as illustrated. The filter unit 11b is formed by connecting a series circuit
including an inductor L4, a resistor R4, and a capacitor C4 and a parallel circuit including an
inductor L5, a resistor R5, and a capacitor C5 as illustrated. The filter unit 11c is formed by
connecting a parallel circuit including an inductor L6 and a resistor R6 and a series circuit
including a resistor R7 and a capacitor C7 as illustrated. FIG. 12 shows an example of the
frequency characteristic of the sub audio when the frequency characteristic of the main audio is
set as the flat characteristic of the reference. As shown in the characteristic portion A, the
frequency characteristic of this sub-audio first drops gradually in voltage (amplitude) as it goes
from the low band to the high band, and then the characteristic portion B , C, dips occur at two
certain frequency points in the midrange. In a band higher than this, as shown as a characteristic
portion D, the voltage gradually decreases. The filter 11 shown in FIG. 11 receives an audio
signal (original audio signal) having a characteristic corresponding to the main audio component
to provide the signal characteristic shown in FIG. 12, and the characteristic of the characteristic
portion D is obtained by the inductor L1. The characteristic of the characteristic portion B is
given by the filter portion 11a, the characteristic of the characteristic portion C is given by the
filter portion 11b, and the characteristic of the characteristic portion A is given by the filter
portion 11c.
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[0064]
Note that the configuration example of the filter 11 as an analog circuit shown in FIG. 11 is
merely an example, and for example, as long as the characteristics as shown in FIG. The following
circuit configuration may be adopted.
[0065]
Further, for example, under the basic configuration shown in FIG. 3, the delay unit 12 is provided
together with the filter 11 for the system of the sub audio component.
As described above, the delay unit 12 is configured to create a difference between the time for
the main audio component to reach the ear from the sound source and the time for the auxiliary
audio component to reach the other ear. Ru. However, in the configuration as the simplified
signal processing system shown in FIG. 7, an embodiment in which this delay unit 12 is omitted
is shown for the LFch, RFch, LSch, and RSch sub-audio systems. That is, in the headphone sound
reproduction system according to the present embodiment, as described below, the
corresponding delay time is obtained by the system that outputs the sub audio component itself,
and for this reason, the delay unit can be omitted. .
[0066]
First, in the system to which the secondary audio component is to be output, the filter 11 for
providing the frequency characteristic difference to the primary audio component is provided as
described above. As a general matter, passing a signal through a filter causes a phase difference
with respect to the input signal. This phase difference can be viewed as a delay of the signal.
Also, as shown in FIG. 4 and FIG. 8 etc., the drive unit to which the sub audio should be output is
the drive unit (SPu-L, SPu-R) (SPu-LR, SPu-RF) of the reference channel in the audio unit. ) Are
spaced apart by a certain distance (DS1), so that a delay in time to reach the ear is obtained.
Thus, in the headphone sound reproduction system of the present embodiment, a corresponding
delay time is given in the path until the sound signal of the sub sound component reaches the ear
as sound. Therefore, if the delay time obtained in this way falls within an error within the
allowable range with respect to the delay time to be actually set by the delay unit 12, the delay
unit 12 in the system can be omitted. It becomes.
10-05-2019
29
[0067]
In addition, in the case of configuring a headphone sound reproduction system compatible with
5.1 ch surround, strictly speaking, as described above with reference to FIG. 23, assuming, for
example, LFch and RFch as the standard, It is necessary to give the signal characteristic
difference of the sound of the other channel (Cch, LSch, RSch) with respect to the channel to
obtain the sound in which the appropriate transfer function is convoluted. However, in the
configuration of FIG. 7, the filters for the main voice component are omitted for Cch, LSch, and
RSch. That is, the filter for giving the signal characteristic difference to the sounds of LFch and
RFch is omitted. Also in this embodiment, in the acoustic unit, drive units corresponding to the
respective output channels are individually arranged. That is, in the present embodiment, as
described above with reference to FIG. 8, for example, drive units are arranged corresponding to
the sound source position of each channel forming 5.1 ch surround, which is preferable. This is a
major factor in achieving good sound image localization. That is, according to the arrangement
positional relationship of the drive unit in the acoustic unit, an operation equivalent to giving a
signal characteristic difference to the sound of, for example, LFch and RFch is obtained. In the
case of FIG. 7, a configuration equivalent to inserting the Cch, LSch, RSch filters 11-C, 11-LS, 11RS shown by the broken line is obtained. It will be. In addition, in FIG. 7, the form which
abbreviate | omitted the delay device 12-C is shown as shown with a broken line also about the
system of Cch. The Cch system can be treated as if the signal characteristic difference between
the sounds reaching the left and right ears does not exist, for example, as the signal characteristic
difference with respect to the main audio component of the reference LFch and RFch, the delay
time difference thereof. Will also be included. The delay device 12-C is originally intended to
generate the delay time difference accurately, but the delay device 12-C can be omitted
depending on the arrangement position of the drive unit described above. . In other words, drive
units SPu-C (L) and SPu-C (R) corresponding to the left and right Cch respectively have a fixed
distance to the front with reference to the position of the speaker units SPu-L and SPu-R. They
are spaced apart, which results in a delay for the time of arrival of the sound to each ear.
Therefore, even if the delay unit 12-C is omitted, a signal characteristic equivalent to the
provision of the delay unit 12-C can be obtained by using the delay of the arrival time of the
sound due to the arrangement position of the drive unit. It is a thing. Thus, in the headphone
sound reproduction system according to the present embodiment, the filter and the delay unit
are omitted in the signal system corresponding to each output channel, and an analog circuit is
adopted as the filter, etc. The simplification of the configuration can be achieved. This is expected
to achieve, for example, significant cost reduction.
10-05-2019
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[0068]
Subsequently, as a simplification measure for the headphone sound reproduction system
according to the present embodiment, the configuration example of a drive unit reduced type
headphone sound reproduction system is considered in which the number of drive units in the
sound unit is reduced. This will be described with reference to FIG.
[0069]
First, FIG. 13 shows a configuration example of a signal system as a drive unit reduction type
headphone sound reproduction system.
In this figure, the same parts as in FIG. 7 will be assigned the same reference numerals and
explanations thereof will be omitted. Synthesizers 13a, 13b, 13c and 13d are provided as signal
systems shown in this figure. First, depending on the synthesizer 13a, a voice signal to which the
transfer function sHrfl corresponding to the sub-voice component of RFch should be convoluted,
and a voice signal to which the transfer function sHcl corresponding to the sound of Cch
reaching the left ear should be folded. Is to be synthesized. Then, the output of the synthesizer
13a is input to the drive unit SPu-f (RF) C provided in the left acoustic unit 1L as an audio signal
of the output channel f (RF) + C. Further, depending on the synthesizer 13b, a speech signal to
which the transfer function sHlfr corresponding to the sub-voice component of LFch should be
convoluted, and a speech signal to which the transfer function sHcr corresponding to the sound
of Cch reaching the right ear should be convoluted Are synthesized and input to the drive unit
SPu-f (LF) C provided in the right acoustic unit 1R as an audio signal of the output channel f (LF)
+ C. Further, the synthesizer 13c synthesizes an audio signal to be convoluted with the transfer
function sHrsl and an audio signal of LFEch to be output from the left acoustic unit 1L, which
corresponds to the sub-audio component of RSch, and outputs the output channel f ( The audio
signal of RS) + LFE is input to the drive unit SPu-f (RS) LFE provided in the left acoustic unit 1L.
Further, the synthesizer 13d synthesizes an audio signal to be convoluted with the transfer
function sHlsr and an audio signal of LFEch to be output from the right acoustic unit 1R, which
corresponds to the sub-audio component of LSch, and outputs the output channel f ( The audio
signal of LS) + LFE is input to the drive unit SPu-f (LS) LFE provided in the right audio unit 1R.
[0070]
That is, in the present embodiment, the number of f (RF), C (L), f (LF), and f (LF) among the 12
output channels that are originally supposed to be six for each of the left and right acoustic units.
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31
A combination of C (R), f (RS) and LFE (L), f (LS) and LFE (R) is synthesized at the audio signal
stage and output from a common drive unit. As a result, as can be seen from the same FIG. 13,
there are four drive units provided in the left sound unit 1L and the right sound unit 1R. That is,
in comparison with FIG. 7, the number of drive units is reduced by two each in the left acoustic
unit 1L and the right acoustic unit 1R, and the total is reduced from 12 to 8.
[0071]
Further, an arrangement example of the drive unit in the acoustic unit corresponding to the
configuration shown in FIG. 13 is shown in FIG. 14 and FIG. As shown in these figures, first, in
the left acoustic unit 1L, drive units SPu-f (RF) C, SPu are arranged from the front to the rear so
that the center position of the sound producing portion is along the horizontal imaginary line H. LF, SPu-LS, SPu-f (RS) LFE are arranged. Also in the right acoustic unit 1R, drive units SPu-f (LF)
C, SPu-RF, SPu-RS, and SPu- are arranged from the front to the rear so that the center position of
the sound producing unit is along the horizontal virtual line H. The f (LS) LFE is arranged. At this
time, drive units SPu-f (RF) C, SPu-LF, SPu-LS, and SPu-f (RS) LFE on the left, and drive units SPu-f
(LF) C, SPu-RF, SPu-RS, on the right. The SPu-f (LS) LFEs are arranged to be symmetrical in left
and right.
[0072]
Here, the sound source positions of the sound components of the respective channels to be
output from the drive unit SPu-f (RF) C and the drive unit SPu-f (LF) C are all supposed to be in
front of the listener. . The drive unit SPu-f (RF) C and the drive unit SPu-f (LF) C are located in
front of the ear in the left acoustic unit 1L and the right acoustic unit 1R, respectively. ,
Corresponding to the incoming direction of the sound from the sound source. As a result, for the
sound of each channel of LFch, RFch, and Cch including the sound component output from drive
unit SPu-f (RF) C and drive unit SPu-f (LF) C, sound image localization that is considered
appropriate is obtained. To be The other drive units SPu-f (RS) LFE and SPu-f (LS) LFE are
arranged on the rear side of the ear, respectively, so that these drive units SPu-f (RS) LFE The
RSch sub-voice and LSch sub-voice output from the SPu-f (LS) LFE also correspond to the
direction of arrival of sound from the RSch and LSch source positions. Therefore, with regard to
the sounds of RSch and LSch, an appropriate sense of sound image localization can be obtained.
In addition, as for the sound of LFEch, as described above, there is no need to consider the sense
of sound image localization due to its frequency characteristics.
10-05-2019
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[0073]
By the way, as described above, in the multi-channel configuration, when voice components of
different channels are synthesized at the stage of the voice signal, phase interference, etc. is not
localized as in the case of being synthesized in space. There is a problem that it is easy to lead to
damage. From this point of view, the above headphone unit reduced type headphone sound
reproduction system also includes the above-mentioned problems in terms of the configuration.
However, in the configuration of the headphone sound reproduction system of the headphone
unit reduction type, for example, in the multi-channel configuration as 5.1 ch surround, the
correlation of the audio signal regarding characteristics such as waveform and frequency band is
as low as possible. The above-mentioned problem is avoided by synthesizing speech signals. That
is, in the above configuration, first, the sub-voice component (f (RF)) of RFch and the voice of Cch,
or the sub-voice component (f (LF)) of LSch, and the voice of Cch are synthesized. For example,
according to an actual 5.1ch surround sound source, if Cch is playing a voice such as a person
located at the center of the screen, in LFch or RFch, the voices of people around it, loud noises,
etc. In many cases, such as LFch or RFch and Cch, the reproduction content is different. That is,
when viewed as an audio signal, it can generally be said that the correlation between waveforms
of LFch and RFch and Cch is low. Also, since the LFEch sound is concentrated at a very low
frequency compared to the sound of other channels, the correlation with the frequency band is
very low even in contrast to, for example, LSch, RSch sub-voice, etc. . In this way, by combining
speech signals having low correlation in signal characteristics, the possibility of phase
interference is low, and in conjunction with this, a phenomenon that the sense of sound image
localization is impaired is also included. It is less likely to occur. That is, the listener can listen to
the sound in a state in which good sound image localization is maintained.
[0074]
Further, a modification of the arrangement of the drive unit in the sound unit with respect to the
above-mentioned drive unit reduced type headphone sound reproduction system is shown in FIG.
The arrangement of the drive unit shown in this figure is an application of the arrangement
example shown in FIG. 10 to the headphone device of the drive unit reduction type. That is, as
shown in the figure, among the drive units provided in the left acoustic unit 1L, the drive units
SPu-f (RF) C and SPu-LF are disposed along the virtual horizontal line H as in FIG. On the other
hand, drive units SPu-LS and SPu-f (RS) LFE that output sound components corresponding to
channels that become sound source positions behind the listener are set at a position higher than
the virtual horizontal line H by a predetermined amount It is arranged along the virtual
horizontal line Hu. Similarly, in the right acoustic unit 1R, the drive units SPu-f (LF), C (R) and
SPu-RF are disposed along the virtual horizontal line H, and the drive units SPu-RS and SPu-f (LS)
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are arranged. The LFE is arranged along the virtual horizontal line Hu. With such an
arrangement, as described in FIG. 10, a better feeling of sound field can be obtained.
[0075]
The setting of measurement points in the space measurement ranges P1 and P2 corresponding
to the drive unit reduced type configuration is also shown in FIG. 15 (or FIG. 16) and the
arrangement aspect of the drive unit viewed from the plane direction shown in FIG. It is made to
correspond to the arrangement of the drive unit as viewed from the side direction shown. In this
case, for the measurement points corresponding to a plurality of audio components synthesized
and output from the same one drive unit, the same appropriate positions are set.
[0076]
In addition, although the configuration for simplifying the configuration of the signal system of
FIG. 7 has been described above, in the present application, on the other hand, the purpose is to
reproduce a very faithful sound field. There is no hindrance to constructing a signal system as In
this case, for example, as the filter 11 and the delay unit 12 shown by broken lines in FIG. 7 are
actually provided, appropriate pass band characteristics and delay time are set, and between the
main audio component and the sub audio component. The signal system is configured in such a
way that a precise signal characteristic difference is given, that is to say a correspondingly
accurate transfer function is convoluted. At this time, for example, if a digital filter is used also
for the filter 11, the accuracy is enhanced.
[0077]
Further, in FIG. 7, the signal system of the main audio component of LFch and RFch as a
reference is not provided with a filter and a delay unit. As described above, with regard to LFch
and RFch, for example, it is intended to easily obtain the required signal characteristics by
utilizing the acoustic characteristics which the headphone device is supposed to have, for
example. However, strictly, for example, as also shown in FIG. 5, a transfer function
corresponding to the sound source position exists for the main audio components of LFch and
RFch, and this transfer function is originally true By being folded in, the sense of localization of
the sound source becomes better. From this point of view, it is also possible to provide filters
(and delays) for the signal systems of the main audio components of LFch and RFch so that
10-05-2019
34
appropriate signal characteristics can be obtained. In this case, for the sounds corresponding to
output channels other than LSch and the main audio component of RFch, the main audio of LFch
and RFch to be given through the filter (and the delay unit) as described above. The signal
characteristic difference may be obtained on the basis of the signal characteristic of the
component.
[0078]
Here, as a headphone sound reproduction system according to the present embodiment, a
headphone device which a listener actually wears on the head and uses, and a signal processing
circuit corresponding to a signal system shown in, for example, FIG. It should be configured with
a department. As a combination of an actual configuration of the headphone device and the
signal processing circuit unit, for example, a system configuration in which the headphone device
and the signal processing device unit including the signal processing circuit unit are separately
provided. Is considered. In this case, transmission of an audio signal from the signal processing
unit to the headphone device may be performed by, for example, wired communication, or may
be performed wirelessly by adopting a predetermined wireless transmission and reception
method using infrared rays, radio waves, and the like. May be In addition, as another
configuration, a configuration may be considered in which a signal processing circuit unit is built
in and integrated with a predetermined portion such as an audio unit or a headband portion that
configures the headphone device main body.
[0079]
By the way, as a single headphone device, one having a configuration in which an independent
drive unit corresponding to a multi-channel is provided in an audio unit is already known. The
configuration of this headphone device is shown in FIG. 24 and FIG. This headphone device is
also intended to correspond to 5.1 ch surround as an audio source. In the headphone device
shown in these figures, first, as shown in FIG. 24, in the left acoustic unit 1L, the drive unit SPuLF corresponding to LFch is disposed at the front position, and Cch is supported at the rear
upper position. The drive unit SPu-C is disposed, and further, the drive unit SPu-LS
corresponding to LSch is disposed at the rear lower position, and the drive unit SPu-LFE
corresponding to LFEch is disposed on the lower side. Further, in the right acoustic unit 1R, the
drive unit SPu-RF corresponding to RFch is disposed at the front position, the drive unit SPu-C
corresponding to Cch is disposed at the rear upper position, and the rear lower side is further
disposed. The drive unit SPu-RS corresponding to LSch is disposed at the position, and the drive
unit SPu-LFE corresponding to LFEch is disposed on the lower side. Then, as shown in FIG. 25,
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audio signals of LFch and RFch are directly input to drive units SPu-LF and SPu-RF, respectively,
and audio of the same Cch is applied to left and right drive units SPu-C. The branched signal is
directly input, and the LSch and RSch voice signals are directly input to the drive units SPu-LS
and SPu-RS, respectively. Further, to the left and right drive units SPu-LFE, the audio signal of
LFEch is directly input.
[0080]
That is, in the headphone device shown in FIGS. 24 and 25, according to the sound source
position of the 5.1ch surround channel for the moment, the LFch and LSch and the RFch and
RSch are distributed to the left sound unit and the right sound unit. For the Cch, a drive unit is
provided for the left and right acoustic units for the Cch because the drive unit needs to be
located at the center of the head, and the left and right The acoustic unit is provided with a drive
unit. In addition, for each drive unit, for example, the audio signal of each channel forming an
audio source of 5.1 ch surround is directly input without particularly performing the filtering
process and the delay process.
[0081]
In such a configuration, sound of each channel forming 5.1ch surround is output from
independent drive units. However, from each drive unit, only the sound of the original audio
signal of the corresponding channel is emitted, and as in the present embodiment, the main audio
is given the relationship of the appropriate signal characteristics for each channel. The
components of the sub-audio can not be heard with both ears. Also, even if the arrangement
along the front-back direction for drive units corresponding to other than LFEch to give a sense
of localization is seen, for example, the arrangement of other drive units with respect to virtual
line H set based on the position of drive unit SPu-LF in FIG. In particular, regularity is not seen
and it is appropriate. From such a thing, in the headphone device of FIG. 24 and FIG. 25,
although the sound of each channel can be clearly discriminated to some extent, as in the present
embodiment, the appropriate sound image localization as 5.1 ch surround It can be said that it is
very difficult to get a feeling.
[0082]
Here, as a headphone sound reproduction system according to the present embodiment, a
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36
headphone device which a listener actually wears on the head and uses, and a signal processing
circuit corresponding to a signal system shown in, for example, FIG. It should be configured with
a department. As a combination of an actual configuration of the headphone device and the
signal processing circuit unit, for example, a system configuration in which the headphone device
and the signal processing device unit including the signal processing circuit unit are separately
provided. Is considered. In this case, transmission of an audio signal from the signal processing
unit to the headphone device may be performed by, for example, wired communication, or may
be performed wirelessly by adopting a predetermined wireless transmission and reception
method using infrared rays, radio waves, and the like. May be In addition, as another
configuration, a configuration may be considered in which a signal processing circuit unit is built
in and integrated with a predetermined portion which is considered to constitute the headphone
device main body.
[0083]
The present invention should not be limited to the configuration as the embodiment described
above. First, the aspect of the physical arrangement of the drive unit to be provided with respect
to the acoustic unit may be considered other than those illustrated so far and the variations
described so far. In addition, although the configuration corresponding to 5.1 ch surround is
taken as an example as an embodiment, the present invention is also applicable to multi-channel
configurations of other systems such as 7.1 ch surround, for example.
[0084]
It is a figure which shows the basic acoustic model corresponding to the headphone acoustic
reproduction system as embodiment of this invention. It is a figure which shows the example of a
setting of the measurement position corresponding to the sound component of each sound
source in the acoustic model of FIG. It is a figure which shows the structural example of the audio
| voice signal processing system about the headphone sound reproduction system corresponding
to FIG. It is a figure which shows the example of a layout aspect of the drive unit in the
headphone apparatus corresponding to the structure of FIG. It is a figure which shows the
acoustic model of 5.1ch surround corresponding to the headphone acoustic reproduction system
of embodiment. It is a figure which shows the example of a setting of the measurement position
corresponding to the sound component of each sound source in the acoustic model of FIG. It is a
figure which shows the structural example of the audio | voice signal processing system of the
headphone sound reproduction system of embodiment corresponding to a 5.1ch surround
system. It is a figure which shows typically the arrangement mode example of the drive unit in
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the headphone apparatus of embodiment corresponding to a 5.1ch surround system from a
plane direction. It is a figure which shows typically the example of a layout aspect of the drive
unit in the headphone apparatus of embodiment corresponding to a 5.1ch surround system from
a side direction. It is a figure which shows typically the example of another arrangement mode
about the drive unit in the headphone apparatus of embodiment corresponding to a 5.1ch
surround system from a side direction. It is a circuit diagram showing an example of composition
of a filter with which an audio signal processing system of a headphone sound reproduction
system of an embodiment is equipped. It is a figure which shows the example of a characteristic
of the filter shown in FIG. It is a figure which shows the structural example of a drive unit
reduction type | mold type as an audio | voice signal processing system of the headphone
acoustic reproduction system of embodiment corresponding to a 5.1ch surround system. It is a
figure which shows typically the example of arrangement | positioning aspect of the drive unit in
the headphone device corresponding to FIG. 13 from a plane direction. It is a figure which shows
typically the example of arrangement | positioning aspect of the drive unit in the headphone
apparatus corresponding to FIG. 13 from a side direction. It is a figure which shows typically the
other example of arrangement | positioning aspect about the drive unit in the headphone
apparatus corresponding to FIG. 13 from a side direction. It is a figure which shows the example
of an acoustic model in the case of listening to one sound source. FIG. 18 is a diagram showing
the signal characteristic difference between the main sound component and the sub sound
component in the acoustic model of FIG. 17; It is a figure which shows the example of an acoustic
model in the case of listening to two sound sources. FIG. 20 is a view showing an example of the
configuration of an audio signal processing system of the headphone sound reproduction system
corresponding to the sound model shown in FIG. 19;
FIG. 21 is a diagram schematically illustrating an arrangement mode example of the drive unit in
the headphone device corresponding to FIG. 20 from a plane direction. It is a figure which shows
the general acoustic model of 5.1ch surround. It is a figure which shows the structural example
of the audio | voice signal processing system of the headphone acoustic reproduction system
corresponding to the acoustic model shown in FIG. It is a figure which shows the example of a
layout aspect of the drive unit in the headphone apparatus corresponding to a multi-channel
structure from planar direction. It is a figure which shows the example of a layout aspect of the
drive unit in the headphone apparatus corresponding to a multi-channel structure from a side
direction.
Explanation of sign
[0085]
1L left acoustic unit, 1R right acoustic unit, 11 (11-LS, 11-RS, 11-f (RS), 11-f (LS), 11-C, 11-f (LF),
10-05-2019
38
11-f (RF )) Filter, 12 (12- (RF), 12-f (RS), 12- (LF), 12-f (LS)) Delay device, SPu-f (RF), SPu-C (L),
SPu -LF, SPu-LS, SPu-f (RS), SPu-LFE (L), SPu-f (LF), SPu-C (R), SPu-RF, SPu-RS, SPu-f (LS), SPu-LFE
(R), SPu-f (RS) LFE (L), SPu-f (LS) LFE (L), SPu-f (RF) C, SPu-f (LF) C drive unit
10-05-2019
39
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